Download the font zip file from any site, such as Google fonts: https://fonts.google.com/
Unzip the font file and upload via FTP to your Wordpress theme folder under fonts. If a fonts folder doesn't exist create a folder named fonts
Open the main sytyle sheet style.css in your them and add the following code:
@font-face {
font-family: font name referenced in style sheet;
src: url (https://www.yourwebsite/wp-content/themes/themename/fonts/fontfile.ttf);
font-weight: normal;
}
Example:
If uploading Futura font files in theme meris
@font-face {
font-family: Futura Bk BT;
src: url (https://www.acfcrashsupplies.com/www.recycledtimberdiscounters.com.au/wp-content/themes/meris/fonts/Futura-XBlk-BT.ttf);
font-weight: normal;
}
for more info click here.